The present invention relates generally to switch device structured such that pressing force to handling knob is transmitted to push switch through link member, and more particularly, to a switch device utilizing push switch provided with push lock mechanism.
For example, as the switch device for fixing to vehicle, in an article that meates various limitation for the mounting place of handling knob or the receiving space of push switch and the like, there is a matter that push switch can not be executed by direct pushing operation with handling knob, in that case, switch device made to transmit the pressing force to handling knob to push switch through link member is employed.
FIG. 4 is a schematic structural diagram illustrating conventional example of switch device of this kind and in the drawing, numeral 1 represents handling knob, said handling knob is rotatably supported to casing 2 such as pannel and the like by pivot 1a means, and being urged counterclockwise by torsion coil spring 3. Numeral 4 is push switch, said push switch 4 has driving bar 4a protruding to upward, and being structured such that when the driving bar 4a reciprocates to up and downward, movable contact point contained within interior is contacted or released to fixed contact point (both are not shown) so that switching of ON: OFF is excuted. Slider 5 is coupled to said driving bar 4a, and said slider 5 is defined to move only up and down direction in the drawing by said casing 2, and elongated hole 5a is provided at its upper side portion. And, numeral 6 represents link member, one end of said link member 6 is pivotally supported to said handling knob 1 by supporting shaft 6a, and other end is coupled to said elongated hole 5a by connecting pin.
In the switch device constructed as above, in case that the handling knob 1 is not pressed, the driving bar 4a is located at the raised position shown in FIG. 4 by the resilient force of returning spring (not shown) contained therein, and the push switch 4 is at OFF state. In this case, if there is some little dimensional variation at the handling knob 1 and the link member 6 as well as the slider 5, these variation is absorbed by the relative movement of the elongated hole 5a and the connecting pin 6b, and the position of handling knob 1 is determined with predetermined angle relative to the casing 2. When the handling knob 1 is presed in the direction fo arrow by finger and the like and being turned counterclockwise around the supporting shaft from a state of FIG. 4, since firstly the connecting pin 6b of the link member 6 drops within the interior of the elongated hole 5a and next the slider 5 drops at a timepoint that the connecting pin 6b is abutted to the bottom of the elongated hole 5a, the driving bar 4a is pressed down and the push switch 4 is switched from OFF to ON. And, when the pressing force to said handling knob 1 is taken off, the driving bar 4a and the slider 5 are raised by the returning spring contained within the bush switch 4, the handling knob 1 and the link member 6 are returned to the position of FIG. 4 by the torsion coil spring 3, and the push switch 4 becomes OFF state again.
Inasmuch as the switch constructed as aforementioned is the one that when the handling knob 1 is pressed, the slider 5 is dropped, and when its pressing force is removed, the slider 5 is raised; in case of using the one that is automatically returned without being locked at ON position of the driving bar 4a, the movement of the handling knob 1 and the slider 5 can be synchronized. However, in case of the push switch of type that when the push switch provided with push lock mechanism, i.e., the driving bar is pressed, it is locked at ON position, and when pressed again, the lock is released and the driving bar is raised, since the connecting pin 6b is possible to be moved up to the top end of the elongated hole 5a against the slider 5 located at the lock position, the handling knob 1 is returned by the torsion coil spring 3 despite the slider 5 is locked at the dropped position, and therefore, there is disadvantage that the movement of the handlijg knob 1 and the slider 5 can not be synchronized.